Role of TBP on the extraction of trivalent f-cations with CMPO dissolved in a room temperature ionic liquid

Abstract

ABSTRACTA detailed study on solvent extraction and optical spectroscopy was performed to understand the extraction of trivalent actinides by the solutions of CMPO (octylphenyl-N,N-diisobutyl-carbamoyl methyl phosphine oxide) in a room temperature ionic liquid (RTIL), viz. 1-butyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide, [C4mim][NTf2]. Solvent extraction studies of Am(III) from nitric acid solution indicated an ion-exchange extraction mechanism. Slope analyses on the distribution data revealed that the stoichiometry of the extracted complex of Am3+/CMPO changed from 1:3 (Am/CMPO) in the absence of tri-n-butyl phosphate (TBP) to 1:2 in the presence of TBP. The distribution ratio values of Am(III) decreased significantly in the presence of TBP suggesting that the latter has an important role in the complexation of CMPO with the metal ion. The extraction of acid increased many folds in the presence of TBP as compared to the bare CMPO solution. The absorption and emission spectra of the extracted complex in RTIL differ significantly in the presence and absence of TBP, signifying the role of TBP in the CMPO-RTIL solvent.